Benthic habitat maps, including maps of seabed sediments, have become critical spatial-decision support tools for marine ecological management and conservation. Despite the increasing recognition that environmental variables should be considered at multiple spatial scales, variables used in habitat mapping are often implemented at a single scale. The objective of this study was to evaluate the ...

abstract wenner direct contact method is a method of estimating apparent electrical conductivity (eca) of agricultural soils in situ. this method can be affected by factors such as quality of electrodes in contact with soil, type of employed electric current, moisture content, clay content and compaction of soil. in this research, the effect of electrode type (rod and plate) and electric curren...

In ratifJingthe United Nations Convention on the Law of the Sea in 1994, Australia took responsibility tor a marine jurisdiction that is more than 1.5 times the area of the landmass. While ownership of offshore resources provided under UNCLOS hestows certain rights (including exploitation), it also carries a range of obligations, including the protection and preservation of the marine environme...

The multibeam echo sounders (MBES) can acquire accurate positional but low-resolution seabed terrain and images, whereas side scan sonars (SSS) can only acquire inaccurate positional but high-resolution seabed images. In this study, a new method for superimposing corrected-positional SSS images on multibeam bathymetric terrain is proposed to obtain high-resolution and accurate-positional seabed...

Measurements of the transmission of seismic survey signals in Australian waters are presented. The measured transmission loss showed: high variability of received signal sound exposure level at similar ranges when comparing all surveys (mean of standard deviation across ranges of 3-12 dB); high variability within a seismic survey (mean of standard deviation at any range of 2-4 dB); typical shot...

Recently, a method has been developed that exploits the correlation properties of the ocean's ambient noise to measure water depth (a passive fathometer) and seabed layering [M. Siderius et al., J. Acoust. Soc. Am. 120, 1315-1323 (2006)]. This processing is based on the cross-correlation between the surface noise and the echo return from the seabed. To quantitatively study the dependency betwee...

This work concerns modeling of very high frequency (>100 kHz) sonar images obtained from a sandy seabed. The seabed is divided into a discrete number of ID height profiles. For each height profile the backscattered pressure is computed by an integral equation method for interface scattering between two homogeneous media as formulated by Chan [IEEE Trans. Antennas Propag. 46, 142-149 (1998)]. Ho...

There is a need for fit-for-purpose maps for accurately depicting the types of seabed substrate and habitat and the properties of the seabed for the benefits of research, resource management, conservation and spatial planning. The aim of this study is to determine whether it is possible to predict substrate composition across a large area of seabed using legacy grain-size data and environmental...